Apparatus and method for configuring radio link control layer parameter for direct communication in a wireless communication system

ABSTRACT

The present disclosure relates to a communication method and system for converging a 5 th -Generation (5G) communication system for supporting higher data rates beyond a 4 th -Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Disclosed is a method of operating a user equipment UE in a wireless communication system, including determining a data transmission rate requirement of a vehicle-to-everything (V2X) application and acquiring data rate information according to the required data transmission rate, transmitting the data rate information to a base station and acquiring a sidelink radio link control (RLC) function configuration parameter, and transmitting the acquired sidelink RLC function configuration parameter to another UE.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. § 119from Korean Patent Application No. 10-2019-0035871, filed on Mar. 28,2019, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated herein by reference in its entirety.

BACKGROUND 1. Field

The disclosure relates generally to a wireless communication system, andmore particularly, to an apparatus and a method for supporting aconfiguration of a sidelink radio link control (RLC) layer parameterrequired for data transmission by a direct communication bearer in awireless communication system.

2. Description of Related Art

To meet the demand for wireless data traffic having increased since thedeployment of fourth generation (4G) communication systems, efforts havebeen made to develop an improved fifth generation (5G) or pre-5Gcommunication system, also referred to as a beyond 4G network” or a postlong term evolution (LTE) system.

The 5G communication system is considered to be implemented in higherfrequency millimeter wave (mmWave) bands, e.g., 60 GHz bands, so as toaccomplish higher data rates. To decrease propagation loss of the radiowaves and increase the transmission distance, the beamforming, massivemultiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO),array antenna, an analog beam forming, large scale antenna techniquesare discussed in 5G communication systems.

In addition, development for system network improvement in 5Gcommunication systems is under way based on advanced small cells, cloudradio access networks (RANs), ultra-dense networks, device-to-device(D2D) communication, wireless backhaul, moving network, cooperativecommunication, and coordinated multi-points (CoMP), reception-endinterference cancellation, for example.

In the 5G system, hybrid frequency shift keying (FSK), quadratureamplitude modulation (QAM) and sliding window superposition coding(SWSC) as an advanced coding modulation (ACM), and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have also beendeveloped.

The 5G system is considering supports for more various services ascompared to the conventional 4G system. For example, the mostrepresentative service may include an ultrawide band mobilecommunication service (enhanced mobile broad band (eMBB)), an ultrahighreliable/low latency communication service (ultra-reliable and lowlatency communication (URLLC)), a massive device-to-device communicationservice (massive machine type communication (mMTC)), and anext-generation broadcast service (evolved multimediabroadcast/multicast service (eMBMS)). A system providing the URLLCservice may be referred to as a URLLC system, and a system providing theeMBB service may be referred to as an eMBB system. The terms “service”and “system” may be interchangeably used.

Among these services, the URLLC service that is a new service underconsideration in the 5G system in contrast to the existing 4G systemrequires ultrahigh reliability, such as a packet error rate of about 10%and low latency, such as about 0.5 milliseconds (msec), as compared tothe other services. To meet these strict conditions, the URLLC servicemay need to apply a shorter transmission time interval (TTI) than theeMBB service, and various operating schemes employing the same are nowunder consideration.

The Internet is now evolving to the Internet of things (IoT) wheredistributed entities, such as things, exchange and process informationwithout human intervention. The Internet of everything (IoE), which is acombination of the IoT technology and the big data processing technologythrough connection with a cloud server, has emerged. As technologyelements, such as “sensing technology”, “wired/wireless communicationand network infrastructure”, “service interface technology”, and“security technology” have been demanded for IoT implementation, asensor network, a machine-to-machine (M2M) communication, and machinetype communication (MTC) have been recently researched.

Such an IoT environment may provide intelligent Internet technologyservices that create a new value to human life by collecting andanalyzing data generated among connected things. IoT may be applied to avariety of fields including smart home, smart building, smart city,smart car or connected cars, smart grid, health care, smart appliancesand advanced medical services through convergence and combinationbetween existing information technology and various industrialapplications.

Accordingly, various attempts have been made to apply 5G communicationsystems to IoT networks. For example, technologies such as a sensornetwork, MTC, and M2M communication may be implemented by beamforming,MIMO, and array antennas. Application of a cloud RAN as theabove-described big data processing technology may also be considered anexample of convergence of 5G with IoT.

In a 5G system, wireless interface schemes for providing servicesmeeting various levels of quality of service (QoS) are being researched.For example, a direct communication scheme for a vehicle-to-everything(V2X) user equipment (UE) has been proposed. V2X refers to all types ofcommunication schemes that can be applied to road vehicles, and variousadditional services, beyond an initial safety application, have becomepossible through convergence with recently developed wirelesscommunication technology. However, there is a need in the art to furtherdecrease a communication time, increase reliability, and moreefficiently support direct communication between UEs.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below.

Accordingly, an aspect of the disclosure is to provide an apparatus anda method for supporting a vehicle communication service and datatransmission that achieve a required high-reliability and low-latencyvalue by providing a method of performing communication through a directcommunication scheme between UEs in a vehicle communication system.

Another aspect of the disclosure is to provide a method of supporting avehicle communication service that requires various levels of quality ofservice (QoS) through direct communication between UEs and a method ofconfiguring an RLC function parameter used for direct communicationbetween UEs in a vehicle communication system, thereby achieving arequired high-speed, high-reliability, and low-latency value.

In accordance with an aspect of the disclosure, a method by a first UEin a wireless communication system includes receiving a first messageincluding RLC function configuration parameter information from a BS,and performing sidelink communication with a second UE, based on thereceived RLC function configuration parameter information.

In accordance with another aspect of the disclosure, a method by a BS ina wireless communication system includes transmitting a first messageincluding RLC function configuration parameter information to a firstUE, wherein sidelink communication between the first UE and a second UEis performed based on the transmitted RLC function configurationparameter information.

In accordance with another aspect of the disclosure, a method by asecond UE in a wireless communication system includes receiving a secondradio resource control (RRC) message from a first UE, transmitting athird RRC message to the first UE in response to the second RRC message,and performing sidelink communication with the first UE, wherein thesecond RRC message is received in case that a condition for configuringa new sidelink radio bearer (SLRB) is satisfied.

In accordance with another aspect of the disclosure, a first UE includesa transceiver configured to transmit and receive at least one signal,and a controller connected to the transceiver, wherein the controller isconfigured to receive a first message including RLC functionconfiguration parameter information from a BS and perform sidelinkcommunication with a second UE, based on the received RLC functionconfiguration parameter information.

In accordance with another aspect of the disclosure, a BS includes atransceiver configured to transmit and receive at least one signal, anda controller connected to the transceiver, wherein the controller isconfigured to transmit a first message including RLC functionconfiguration parameter information to a first UE, and wherein sidelinkcommunication between the first UE and a second UE is performed based onthe transmitted RLC function configuration parameter information.

In accordance with another aspect of the disclosure, a second UEincludes a transceiver configured to transmit and receive at least onesignal, and a controller connected to the transceiver, wherein thecontroller is configured to receive a second RRC message from a firstUE, transmit a third RRC message to the first UE in response to thesecond RRC message, and perform sidelink communication with the firstUE, and wherein the second RRC message is received in case that acondition for configuring a new SLRB is satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a wireless communication system according to anembodiment;

FIG. 2 illustrates the configuration of a BS in a wireless communicationsystem according to an embodiment;

FIG. 3 illustrates the configuration of a UE in a wireless communicationsystem according to an embodiment;

FIG. 4A illustrates the configuration of a communication unit in awireless communication system according to an embodiment;

FIG. 4B illustrates an example in which an analog beamforming unit of acommunication unit uses an independent antenna array for eachtransmission path in a wireless communication system according to anembodiment;

FIG. 4C illustrates an example in which an analog beamforming unit of acommunication unit shares one antenna array for transmission paths in awireless communication system according to an embodiment;

FIG. 5A illustrates direct communication between UEs through a sidelinkradio access technology (RAT) according to a first embodiment; FIG. 5Billustrates direct communication between UEs through a sidelink RATaccording to a second embodiment;

FIG. 5C illustrates direct communication between UEs through a sidelinkRAT according to a third embodiment;

FIG. 5D illustrates direct communication between UEs through a sidelinkRAT according to a fourth embodiment;

FIG. 6A illustrates a method by which a BS configures an RLC functionconfiguration parameter required for configuring a PC5 RRC connectionbetween UEs according to an embodiment;

FIG. 6B illustrates a method by which a UE configures an RLC functionconfiguration parameter required for configuring a PC5 RRC connectionaccording to an embodiment;

FIG. 7 illustrates a signal procedure for operating an RLC functionconfiguration parameter to be applied to sidelink data according to anembodiment;

FIG. 8A illustrates a method of a UE for measuring and reportingcongestion of sidelink resources according to an embodiment;

FIG. 8B illustrates a method of a UE for measuring and reportingcongestion of sidelink resources according to an embodiment;

FIG. 9 illustrates a signal procedure for configuring a sidelinkresource allocation mode according to an embodiment;

FIG. 10A illustrates the signal flow for configuring a new PC5 RRCunicast connection between UEs according to an embodiment;

FIG. 10B illustrates the signal flow for transmitting and receiving aV2X packet through preset PC5 RRC unicast connection configurationinformation according to an embodiment;

FIG. 10C illustrates the signal flow for configuring a new PC5unicast-based SLRB according to an embodiment;

FIG. 11A illustrates a method of a UE for processing a source identifierupdate for sidelink according to an embodiment;

FIG. 11B illustrates a method of a UE for processing a source identifierupdate for sidelink according to an embodiment; and

FIG. 12 illustrates a signal procedure for processing a sourceidentifier update for sidelink according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the disclosure may be described withreference to accompanying drawings. Accordingly, those of ordinary skillin the art will recognize that modifications, equivalents, and/oralternatives on the embodiments described herein can be variously madewithout departing from the scope and spirit of the disclosure. Withregard to description of drawings, similar components may be marked bysimilar reference numerals. Descriptions of well-known functions and/orconfigurations will be omitted for the sake of clarity and conciseness.

The terms used in the disclosure are only used to describe specificembodiments and are not intended to limit the disclosure. A singularexpression may include a plural expression unless they are different incontext. Unless defined otherwise, all terms used herein, includingtechnical and scientific terms, have the same meaning as those commonlyunderstood by a person skilled in the art to which the disclosurepertains. Such terms as those defined in a generally used dictionary maybe interpreted to have the same meanings as the contextual meanings inthe relevant field of art, and are not to be interpreted to have idealor excessively formal meanings unless clearly defined in the disclosure.In some cases, even the term defined in the disclosure should not beinterpreted to exclude embodiments of the disclosure.

Hereinafter, embodiments will be described based on hardware. However,the embodiments include a technology that uses both hardware andsoftware and thus, may also include software.

The disclosure relates to an apparatus and a method for configuring anRLC function parameter to support a V2X service through a directcommunication protocol between UEs in a wireless communication system.Specifically, the disclosure describes technology for satisfying a QoSlevel required for various V2X services based on a method of a UE forconfiguring an RLC parameter required for supporting high-speed datatransmission and high reliability, which are needed for sidelink directcommunication between V2X UEs in a wireless communication system.

Terms referring to a signal used in the following description, termsreferring to a channel, terms referring to control information, termsreferring to network entities, and terms referring to elements of adevice are used only for convenience of description. Accordingly, thedisclosure is not limited to those terms, and other terms having thesame technical meanings may be used.

The disclosure describes embodiments using terms from communicationstandards, such as the 3^(rd)-generation partnership project (3GPP)),but this is only an example. Embodiments herein may be modified andapplied to other communication systems.

A method of operating a UE in a wireless communication system mayinclude determining data rate information required by a V2X application,informing a BS of the required data rate information, acquiring an RLCfunction configuration parameter corresponding to the data rateinformation from the BS, informing another UE of the acquired RLCfunction configuration parameter, and performing directcommunication-based data transmission and reception based on theacquired RLC function configuration parameter.

A UE apparatus in a wireless communication system may include atransceiver and at least one processor functionally connected to thetransceiver. The at least one processor may determine data rateinformation of a V2X application through which the UE transmits andreceives data in a direct communication mode, inform the BS of requireddata rate information, and receive an RLC function configurationparameter corresponding to the required data rate information from theBS. When the UE acquires the RLC function configuration parametercorresponding to the data rate information, the at least one processormay inform another UE of the RLC function configuration parameter.

FIG. 1 illustrates a wireless communication system according to anembodiment.

FIG. 1 illustrates a BS 110, UE #1 120, and UE #2 130 as some of thenodes using a radio channel in a wireless communication system. AlthoughFIG. 1 illustrates only one BS, another BS that is the same as orsimilar to the BS 110 may be further included. Although FIG. 1illustrates only two UEs, another UE that is the same as or similar toUE #1 120 and UE #2 130 may be further included.

The BS 110 is a network infrastructure element that provides radioaccess to the UEs 120 and 130. The BS 110 has coverage defined in apredetermined geographical area based on the range within which a signalcan be transmitted and received. The BS 110 may be referred to as an“access point (AP)”, “eNodeB (eNB)”, “5^(th)-generation (5G) node”, “5GnodeB (NB)”, “wireless point”, or “transmission/reception point (TRP)”,or using another term having a technical meaning equivalent thereto.

Each of UE #1 120 and UE #2 130 is used by a user and communicates withthe BS 110 through a radio channel Depending on the circumstances, atleast one of UE #1 120 and UE #2 130 may be operated without userinvolvement. That is, at least one of UEs #1 120 and UE #2 130 performsMTC and may not be carried by the user. Each of UE #1 120 and UE #2 130may be referred to as a “user equipment”, “mobile station”, “subscriberstation”, “remote terminal”, “wireless terminal”, or “user device”, orusing another term having the same meaning, as well as “terminal”.

The BS 110, UE #1 120, and UE #2 130 may transmit and receive a wirelesssignal in a subband of 6 gigahertz (GHz) and mmWave bands (for example,28 GHz, 30 GHz, 38 GHz, and 60 GHz). In order to increase channel gain,the BS 110, the UE #1 120, and the UE #2 130 may perform beamforming,which may include transmission beamforming and reception beamforming.That is, the BS 110, the UE #1 120, and the UE #2 130 may assigndirectivity to a transmission signal or a reception signal. To this end,the BS 110 and the UEs 120 and 130 may select serving beams 112, 113,121, and 131 through a beam search procedure or beam managementprocedure. After the serving beams 112, 113, 121, and 131 are selected,communication may be performed through resources having aquasi-co-located (QCL) relationship with resources through which theserving beams 112, 113, 121, and 131 are transmitted.

If the large-scale characteristics of a channel for transmitting symbolsthrough a first antenna port can be inferred from a channel fortransmitting symbols through a second antenna port, the first antennaport and the second antenna port may be evaluated to have a QCLrelationship therebetween. For example, the large-scale characteristicsmay include at least one of delay spread, Doppler spread, Doppler shift,average gain, average delay, and spatial receiver parameters.

FIG. 2 illustrates the configuration of a BS in a wireless communicationsystem according to an embodiment.

The configuration illustrated in FIG. 2 may be the configuration of theBS 110. The term “ . . . unit” or the ending of a word, such as “ . . .or” or “ . . . er”, may indicate a unit of processing at least onefunction or operation, and may be embodied by hardware, software, or acombination of hardware and software.

Referring to FIG. 2, the BS includes a wireless communication unit 210,a backhaul communication unit 220, a storage unit 230, and a controller240.

The wireless communication unit 210 performs functions for transmittingand receiving a signal through a radio channel. For example, thewireless communication unit 210 performs a function of conversionbetween a baseband signal and a bitstream according to thephysical-layer standard of the system. In data transmission, thewireless communication unit 210 may encode and modulate a transmissionbitstream to generate complex symbols. In data reception, the wirelesscommunication unit 210 reconstructs a reception bitstream bydemodulating and decoding a baseband signal.

In addition, the wireless communication unit 210 up-converts a basebandsignal into a radio-frequency (RF) band signal which it transmitsthrough an antenna, and down-converts an RF band signal received throughan antenna into a baseband signal. To this end, the wirelesscommunication unit 210 may include a transmission filter, a receptionfilter, an amplifier, a mixer, an oscillator, a digital-to-analogconvertor (DAC), and an analog-to-digital convertor (ADC), for example.The wireless communication unit 210 may include a plurality oftransmission/reception paths and at least one antenna array including aplurality of antenna elements.

On the hardware side, the wireless communication unit 210 may include adigital unit and an analog unit. The analog unit may include a pluralityof sub-units according to operating power, operating frequency, and thelike. The digital unit may be implemented by at least one processor,such as a digital signal processor (DSP).

The wireless communication unit 210 transmits and receives a signal asdescribed above. Accordingly, all or part of the wireless communicationunit 210 may be referred to as a “transmitter”, a “receiver”, or a“transceiver”. In the following description, transmission and receptionperformed through a radio channel may include the above-describedprocessing by the wireless communication unit 210.

The backhaul communication unit 220 provides an interface forcommunicating with other nodes within the network. That is, the backhaulcommunication unit 220 converts a bitstream transmitted from the BS toanother access node, another BS, a higher node, or a core network, intoa physical signal, and converts a physical signal received from the nodeinto a bitstream.

The storage unit 230 may store data such as a basic program for theoperation of the BS, an application, and configuration information. Thestorage unit 230 may include at least one of a volatile memory andnonvolatile memory. The storage unit 230 provides stored data inresponse to a request from the controller 240.

The controller 240 may control the overall operation of the BS. Forexample, the controller 240 transmits and receives a signal through thewireless communication unit 210 or the backhaul communication unit 220.The controller 240 records and reads data in the storage unit 230. Thecontroller 240 may perform the functions of a protocol stack requiredfor communication standards. According to another implementation, theprotocol stack may be included in the wireless communication unit 210.To this end, the controller 240 may include at least one processor.

The controller 240 may transmit RRC configuration information to the UEs120 and 130. The controller 240 may transmit sidelink configurationinformation to the UEs 120 and 130. For example, the controller 240 maycontrol the BS to perform operations according to embodiments describedbelow.

FIG. 3 illustrates the configuration of a UE in a wireless communicationsystem according to an embodiment.

The configuration illustrated in FIG. 3 may be the configuration of UE#1 120 or UE #2 130. Referring to FIG. 3, the UE includes acommunication unit 310, a storage unit 320, and a controller 330.

The communication unit 310 performs functions for transmitting andreceiving a signal through a radio channel. For example, thecommunication unit 310 performs a function of conversion between abaseband signal and a bitstream according to a physical-layer standardof the system. In data transmission, the communication unit 310 encodesand modulates a transmission bitstream to generate complex symbols. Indata reception, the communication unit 310 reconstructs a receptionbitstream by demodulating and decoding a baseband signal. Thecommunication unit 310 up-converts a baseband signal to an RF bandsignal, transmits the RF band signal through an antenna, and thendown-converts the RF band signal received through the antenna to thebaseband signal. The communication unit 310 may include a transmissionfilter, a reception filter, an amplifier, a mixer, an oscillator, a DAC,and an ADC.

The communication unit 310 may include a plurality oftransmission/reception paths. The communication unit 310 may include atleast one antenna array including a plurality of antenna elements. Onthe hardware side, the communication unit 310 may include a digitalcircuit and an analog circuit, such as a radio-frequency integratedcircuit (RFIC). The digital circuit and the analog circuit may beimplemented as a single package. The communication unit 310 may includea plurality of RF chains and may perform beamforming.

The communication unit 310 may include different communication modulesfor processing signals in different frequency bands. The communicationunit 310 may include a plurality of communication modules for supportinga plurality of different radio access technologies. For example, thedifferent radio access technologies may include Bluetooth™ low energy(BLE), wireless fidelity (Wi-Fi), Wi-Fi gigabyte, and a cellularnetwork, such as LTE. Different frequency bands may include asuper-high-frequency (SHF) (for example, 2.5 GHz, 3.5 GHz, and 5 GHz)band and an mm wave (for example, 60 GHz) band.

The communication unit 310 transmits and receives a signal, and thus,may be referred to as a “transmitter”, a “receiver”, or a “transceiver”.Transmission and reception performed through a wireless channel mayindicate that the above-described processing is performed by thecommunication unit 310.

The storage unit 320 stores data such as a basic program, anapplication, and configuration information for the operation of the UE.The storage unit 320 may include at least one of a volatile memory andnonvolatile memory. The storage unit 320 provides stored data inresponse to a request from the controller 330.

The controller 330 controls the overall operation of the UE. Forexample, the controller 330 transmits and receives a signal through thecommunication unit 310. The controller 330 records and reads data in thestorage unit 320. The controller 330 may perform the functions of aprotocol stack required by the communication standard. To this end, thecontroller 330 may include at least one processor or microprocessor ormay be a part of the processor. The part of the communication unit 310or the controller 330 may be referred to as a communications processor(CP).

The controller 330 may perform a process of determining a datatransmission requirement of a V2X application for performing sidelinkdirect communication between the UEs 120 and 130 and another UE,informing the BS 110 of required data transmission information,receiving an RLC function configuration parameter corresponding torequired data transmission information from the BS, providing RLCfunction configuration parameter information to another UE, andprocessing data to be transmitted to another UE according to the RLCfunction configuration parameter information. For example, thecontroller 330 may control the UE to perform operations according toembodiments described below.

FIG. 4A illustrates the configuration of a communication unit in awireless communication system according to an embodiment.

Referring to FIG. 4A, the wireless communication unit 210 or thecommunication unit 310 includes an encoding and modulation unit 402, adigital beamforming unit 404, a plurality of transmission paths 406-1 to406-N, and an analog beamforming unit 408.

The encoding and modulation unit 402 performs channel encoding, forwhich at least one of a low-density parity check (LDPC) code, aconvolution code, and a polar code may be used. The encoding andmodulation unit 402 generates modulation symbols by performingconstellation mapping.

The digital beamforming unit 404 performs beamforming on a digitalsignal (for example, modulation symbols). To this end, the digitalbeamforming unit 404 multiplies beamforming weights by modulationsymbols. The beamforming weight values may be used for changing the sizeand phase of the signal and may be referred to as a “precoding matrix”or a “precoder”. The digital beamforming unit 404 outputs digitallybeamformed modulation symbols through the plurality of transmissionpaths 406-1 to 406-N. According to a MIMO transmission scheme, themodulation symbols may be multiplexed, or the same modulation symbolsmay be provided to the plurality of transmission paths 406-1 to 406-N.

The plurality of transmission paths 406-1 to 406-N converts thedigitally beamformed digital signals into analog signals. To this end,each of the plurality of transmission paths 406-1 to 406-N may includean inverse fast Fourier transform (IFFT) calculator, a cyclic prefix(CP) inserter, a DAC, and an up-converter. The CP inserter is for anorthogonal frequency-division multiplexing (OFDM) scheme and may beomitted when another physical layer scheme (for example, a filter bankmulti-carrier (FBMC) scheme) is applied. That is, the plurality oftransmission paths 406-1 to 406-N provides independent signal-processingprocesses for a plurality of streams generated through the digitalbeamforming. However, depending on the implementation, some of theelements of the plurality of transmission paths 406-1 to 406-N may beused in common.

The analog beamforming unit 408 performs beamforming on an analogsignal. To this end, the digital beamforming unit 404 multipliesbeamforming weights by analog signals. The beamforming weights are usedto change the size and phase of the signal. More specifically, theanalog beamforming unit 408 may be configured as illustrated in FIG. 4Bor 4C according to the connection structure between the plurality oftransmission paths 406-1 to 406-N and the antennas.

FIG. 4B illustrates the configuration of a communication unit in awireless communication system according to an embodiment. Referring toFIG. 4B, signals input into the analog beamforming unit 408 may betransmitted through the antennas via phase/size conversion andamplification operation. The signals in respective paths are transmittedthrough different antenna arrays (or sets). In processing of signalsinput through a first path, the signals are converted into signalsequences having the same or different phase/size by phase/sizeconversion units 412-1-1 to 412-1-M, amplified by amplifiers 414-1-1 to414-1-M, and transmitted through antennas.

FIG. 4C illustrates the configuration of a communication unit in awireless communication system according to an embodiment.

Referring to FIG. 4C, the signals input into the analog beamforming unit408 are transmitted through the antennas via phase/size conversion andamplification operation. The signals in respective paths are transmittedthrough the same antenna array. In the processing of signals inputthrough a first path, the signals are converted into signal sequenceshaving the same or different phases/sizes by the phase/size conversionunits 412-1-1 to 412-1-M, and are amplified by the amplifiers 414-1-1 to414-1-M. The amplified signals to be transmitted through one antenna aresummed by summing units 416-1 to 416-M based on antenna elements and arethen transmitted through antennas.

FIG. 4B illustrates an example in which an independent antenna array isused for each transmission path, and FIG. 4C illustrates an example inwhich transmission paths share one antenna array. However, sometransmission paths may use independent antenna arrays and the remainingtransmission paths may share one antenna array. Also, a structure thatmay adaptively vary depending on the situation may be used by applying aswitchable structure between transmission paths and antenna arrays.

A V2X service may be divided into a basic safety service and an advancedservice. The basic safety service may correspond to detailed servicessuch as a vehicle notification ((cooperative awareness messages (CAM) orbasic safety message (BSM)) service, a left-turn notification service, aforward collision warning service, an approaching emergency vehiclenotification service, a forward obstacle warning service, and anintersection signal information service, and may transmit and receiveV2X information through a broadcast, unicast, or groupcast transmissionscheme.

The advanced service has more stringent QoS requirements compared to thebasic safety service, and needs a scheme of transmitting and receivingV2X information through unicast and broadcast transmission schemes,rather than the broadcast transmission scheme, in order to transmit andreceive V2X information within a specific vehicle group or between twovehicles. The advanced service may correspond to detailed services suchas a platooning service, an autonomous driving service, a remote drivingservice, and an extended sensor-based V2X service.

For the V2X service, the UE may perform the V2X service in an ng-RAN(gNB) connected to a 5G core network or an E-UTRAN (ng-eNB) connected toa 5G core network through the ng-RAN or the E-UTRAN. When the BS (ng-RANor ng-eNB) is connected to an evolved packet core (EPC) network, the V2Xservice may be performed through the BS. When the BS is connected to anevolved packet core (EPC) network, the V2X service may be performedthrough the BS. A V2X wireless interface communication scheme that canbe used for direct communication between UEs may be at least one ofunicast, groupcast, and broadcast schemes, and a method of managing andconfiguring a wireless communication parameter suitable for QoSrequirements of the V2X service should be provided when V2Xtransmission/reception is performed in each of the communicationschemes.

A system for performing direct communication between UEs based on LTEwireless communication is defined such that a transmission UE selectsand operates parameters that it requires for transmission. In the caseof LTE wireless communication, a V2X service message for basic safety istransmitted between UEs through a direct communication scheme. QoSrequirements of the basic safety V2X service are not strict, and even ifthere is a variety of basic safety services, the variety of QoSrequirements between services is low, and differences between servicesare minimal. Accordingly, even in a mode in which the BS schedules radioresources to be used for direct communication between UEs based on LTEwireless communication, the BS simply schedules radio resources withoutany need to acquire detailed QoS requirement information of the V2Xservice, and the UE manages and configures parameters.

Advanced V2X services have various QoS requirements, and the QoS levelof each V2X service may greatly vary. A specific advanced V2X servicecan be executed only when radio resources and radio parameters fordirect communication are configured so as to satisfy the strict QoSrequirements of the service. Accordingly, a system based on directcommunication between UEs for supporting the advanced V2X service shouldprovide a better method of guaranteeing QoS than the conventionalsystem.

FIG. 5A illustrates direct communication between UEs through a sidelinkRAT according to a first embodiment. In FIG. 5A, UEs in the gNB coverageperform direct communication. Resource allocation configurationparameter information of a sidelink radio bearer to be used fortransmitting and receiving a V2X packet based on unicast, broadcast, orgroupcast between UEs may be transmitted to the UEs 120 and 130 througha system information message or an RRC-dedicated message of the gNB 110,or may be configured in advance in the UEs 120 and 130. The UEs 120 and130 performing direct communication by NR V2X SL may transmit data rateinformation required by the V2X service packet to the gNB 110 andacquire sidelink resource allocation and/or RLC function configurationparameter information from the gNB 110. The sidelink RLC functionconfiguration parameter information may be transferred to another UE.

FIG. 5B illustrates direct communication between UEs through a sidelinkRAT according to a second embodiment. In FIG. 5B, the UEs 120 and 130 inthe ng-eNB coverage perform direct communication. Resource allocationconfiguration parameter information of a sidelink radio bearer to beused for transmitting and receiving a V2X packet based on unicast,broadcast, or groupcast between UEs may be transmitted to the UEs 120and 130 through a system information message or an RRC dedicated messageof the ng-eNB 110 or configured in advance in the UEs 120 and 130. TheUEs 120 and 130 performing direct communication by NR V2X SL maytransmit data rate information required by the V2X service packet to theng-eNB 110 and acquire sidelink resource allocation and/or RLC functionconfiguration parameter information from the ng-eNB 110. The sidelinkRLC function configuration parameter information may be transferred toanother UE.

FIG. 5C illustrates direct communication between UEs through a sidelinkRAT according to a third embodiment. In FIG. 5C, the UE 120 in the gNBcoverage and the UE 130 in the eNB coverage perform directcommunication. Resource allocation configuration parameter informationof a sidelink radio bearer to be used for transmitting and receiving aV2X packet based on unicast, broadcast, or groupcast between UEs may betransmitted to the UEs 120 and 130 through a system information messageor an RRC dedicated message of the gNB 110, or may be configured inadvance in the UEs 120 and 130. The UEs 120 and 130 performing directcommunication by NR V2X SL may transmit data rate information requiredby the V2X service packet to the gNB 110 and acquire sidelink resourceallocation and/or RLC function configuration parameter information fromthe gNB 110. The sidelink RLC function configuration parameterinformation may be transferred to another UE.

FIG. 5D illustrates direct communication between UEs through a sidelinkRAT according to a fourth embodiment. In FIG. 5D, the UEs 120 and 130 inthe eNB coverage perform direct communication. Resource allocationconfiguration parameter information of a sidelink radio bearer to beused for transmitting and receiving a V2X packet based on unicast,broadcast, or groupcast between UEs may be transmitted to the UEs 120and 130 through a system information message or an RRC dedicated messageof the eNB 110, or may be configured in advance in the UEs 120 and 130.The UEs 120 and 130 performing direct communication by NR V2X SL maytransmit data rate information required by the V2X service packet to theeNB 110 and acquire sidelink resource allocation and/or RLC functionconfiguration parameter information from the eNB 110. The sidelink RLCfunction configuration parameter information may be transferred toanother UE.

The sidelink RLC function configuration parameter for performing directcommunication between UEs may be used to perform PC5 RRC signalingtransmission/reception in the unicast manner, transmit/receive a V2Xmessage in the unicast manner, transmit/receive a V2X message in thebroadcast manner, and transmit/receive a V2X message in the groupcastmanner.

Sidelink direct communication may be used to perform PC5 RRC signalingtransmission/reception used for configuring and managing a unicastconnection between UEs and to transmit/receive V2X data that can beexchanged between UEs in the unicast manner, groupcast manner, andbroadcast manner. Configuration information required for performing PC5RRC signaling transmission/reception may include a functionconfiguration parameter for each layer, such as packet data convergenceprotocol (PDCP), radio link control (RLC), medium access control (MAC),or physical (PHY). Configuration information required fortransmitting/receiving V2X data may include a function configurationparameter for each layer, such as PDCP, RLC, MAC, or PHY. The disclosuredescribes a method of operating the sequence number (SN) size and an ARQconfiguration parameter, among RLC layer functions applied to PC5 RRCsignaling and V2X data. The RLC layer function configuration parametermay be configured according to at least one of a determination method bya UE implementation, a preconfigured method, a method configured by theBS (RRC-dedicated signaling or V2X SIB signaling), and a methodconfigured by the UE (PC5 RRC-dedicated signaling, PC5 MIB, or PC5 SIB).

FIG. 6A illustrates a signal procedure for operating an RLC functionconfiguration parameter to be applied to sidelink RRC according to anembodiment. FIG. 6A illustrates a method by which the BS configures anRLC function configuration parameter required for configuring a PC5 RRCconnection between UEs and informs the UE of the same. The BS mayindicate the configuration of the RLC function configuration parameterrequired for configuring the PC5 RRC connection and/or update theparameter to a new value.

Referring to FIG. 6A, UE #1 600 may determine that a PC5 RRC connectionfor a sidelink unicast connection with UE #2 670 is needed and start aPC5 RRC configuration procedure in step 601. UE #1 600 may transmit aSidelinkUEInformation message to inform a BS 690 of the PC5 RRCconnection configuration in step 602. The BS 690 may configureinformation received from UE #1 600, that is, sidelink radio resourcesand configuration information required for PC5 RRC connectionconfiguration, based on the PC5 RRC connection configurationnotification in step 603. The BS 690 may transmit an RRCReconfigurationmessage or an RRCConnectionReconfiguration message including theinformation configured in step 603 to UE #1 600 in step 604. The messagein step 604 may include RLC function configuration parameter informationrequired for the PC5 RRC connection. An embodiment of the RLC functionconfiguration parameter information may include Table 6, as shown below.

In step 605, UE #1 600 may determine RLC function configurationparameter information for PC5 RRC connection with UE #2 670 based on theRLC function configuration parameter information received in step 604.UE #1 600 may inform UE #2 670 of the RLC function configurationparameter information. UE #1 600 and UE #670 may perform a PC5 RRCconnection configuration procedure based on the RLC functionconfiguration parameter information in step 606. A description of thedetailed procedure of the PC5 RRC connection configuration is omitted.When the RLC function configuration parameter information is notreceived in step 604, UE #1 600 and UE #2 670 may perform the PC5 RRCconnection configuration procedure based on RLC function configurationparameter information set in a default configuration. An embodiment ofthe default configuration is as shown in Table 1, as follows.

TABLE 1 Name Value Signaling SLRB (e.g., SLRB0)PDCP-Config >t-Reordering infinity RLC-Config CHOICE AmSL-RLC-Config >sn-FieldLength size12 >t-PollRetransmit ms45 >pollPDUinfinity >pollByte infinity >maxRetxThreshold t8 >t-Reassemblyms35 >t-StatusProhibit ms0 logicalChannelIdentity 1LogicalChannelConfig >priority 1 >prioritisedBitRateinfinity >logicalChannelGroup 0

UE #600 or UE #2 670 may receive an RRCReconfiguration message, anRRCConnectionReconfiguration message, or a V2X SIB including RLCfunction configuration parameter information for PC5 RRC whiletransmitting and receiving PC5 RRC connection configuration signalingaccording to the default configuration or a preset configuration. Thisprocedure may correspond to step 604, and the embodiment of the RLCfunction configuration parameter information may include Table 6, asshown below.

UE #1 600 and UE #2 670 may transmit and receive PC5 RRC connectionconfiguration signaling according to a new RLC function configurationparameter for PC5 RRC. UE #1 600 and UE #2 670, acquiring the new RLCfunction configuration parameter for PC5 RRC, may inform the counterpartUE (UE #1 or UE #2) of the new RLC function configuration parameter. PC5RRC signaling including the new RLC function configuration parameter forPC5 RRC may be transmitted and received through the application of apre-used RLC function configuration parameter (or defaultconfiguration). The new RLC function configuration parameter for PC5 RRCmay be applied after PC5 RRC complete signaling corresponding to the PC5RRC signaling. For example, the PC5 RRC signaling may include ASconfiguration and AS configuration complete. This procedure maycorrespond to step 606.

FIG. 6B illustrates a signal procedure for operating an RLC functionconfiguration parameter to be applied to sidelink RRC according to anembodiment.

FIG. 6B illustrates a method by which the UE configures an RLC functionconfiguration parameter required for configuring a PC5 RRC connectionand informing the counterpart UE of the parameter. The UE may indicatethe configuration of the RLC function configuration parameter requiredfor configuring the PC5 RRC connection and/or update the parameter to anew value.

Referring to FIG. 6B, UE #1 600 may determine that the PC5 RRCconnection for a sidelink unicast connection with UE #2 670 is neededand start a PC5 RRC configuration procedure in step 621. UE #1 600 maytransmit a SidelinkUEInformation message to inform a BS 690 of the PC5RRC connection configuration in step 622. The BS 690 may configureinformation received from UE #1 600, that is, sidelink radio resourcesand configuration information required for PC5 RRC connectionconfiguration, based on the PC5 RRC connection configurationnotification in step 623. The BS 690 may transmit an RRCReconfigurationmessage and an RRCConnectionReconfiguration message including theinformation configured in step 623 to UE #1 600 in step 624. UE #1 600may determine RLC function configuration parameter information for PC5RRC with UE #2 670 in step 625 as well as the sidelink radio resourcesand configuration information received in step 624. UE #1 600 may informUE #2 670 of the RLC function configuration parameter information.

An embodiment of the RLC function configuration parameter informationmay include Table 6, as shown below. UE #1 600 and UE #670 may perform aPC5 RRC connection configuration procedure based on the RLC functionconfiguration parameter information for PC5 RRC in step 626. Adescription of the detailed procedure of the PC5 RRC connectionconfiguration is omitted.

In step 625, UE #1 600 may determine to use the default configuration ofTable 1 as the RLC function configuration parameter for PC5 RRC with UE#2 670. At this time, UE #1 600 and UE #2 670 may perform the PC5 RRCconnection configuration procedure based on the RLC functionconfiguration parameter information set in the default configuration inTable 1.

Alternatively, UE #1 and UE #2 may determine a change in the RLCfunction configuration parameter while transmitting and receiving PC5RRC connection configuration signaling according to the defaultconfiguration or a preset configuration, which may correspond to step625. UE #1 and UE #2 may transfer PC5 RRC signaling including new RLCfunction configuration parameter information to the counterpart UE,which also includes Table 6. PC5 RRC signaling including the new RLCfunction configuration parameter for PC5 RRC may be transmitted andreceived through the application of a pre-used RLC functionconfiguration parameter (or default configuration). The new RLC functionconfiguration parameter for PC5 RRC may be applied after PC5 RRCcomplete signaling corresponding to the PC5 RRC signaling. For example,the PC5 RRC signaling may include AS configuration and AS configurationcomplete, which may correspond to step 626.

The RLC function configuration parameter that can be applied totransmission/reception of PC5 signaling (for example, signaling SLRB)may include at least one piece of information in Table 2, Table 3, Table4, Table 5 and Table 6, as shown below.

TABLE 2 RLC mode RLC UM mode RLC AM mode SN size  6-bit 12-bit 12-bit18-bit

The RLC function configuration parameter that can be applied totransmission/reception of V2X data (for example, data SLRB) may includeat least on piece of information in Table 3, Table 4, Table 5 and Table6, as shown below.

TABLE 3 RLC mode RLC UM mode RLC AM mode SN size  6-bit 12-bit 12-bit18-bit ARQ parameters PollByte value PollPDU value

The RLC function configuration parameter according to Table 3 above maybe applied to each sidelink unicast-based SLRB, each sidelinkbroadcast-based SLRB, or each sidelink groupcast-based SLRB. The RLCfunction configuration parameter may be configured by at least one of amethod following a UE implementation, a preset method, a methodconfigured by the BS, and a method configured by the UE.

FIG. 7 illustrates a signal procedure for operating an RLC functionconfiguration parameter to be applied to sidelink data according to anembodiment.

Referring to FIG. 7, UE #1 700 may determine sidelink unicast-based V2Xdata transmission with UE #2 770 in step 701. UE #1 700 may transmit aSidelinkUEInformation message to inform a BS 790 of the sidelinkunicast-based V2X data transmission in step 702. The informationprovided through the SidelinkUEInformation message may include arequired data rate.

The information provided through the SidelinkUEInformation message mayinclude at least one of the parameters in Table 4 and Table 5, as shownbelow, at least one piece of information on unicast, groupcast, andbroadcast, and at least one of a destination identifier, a ProSeQosindicator (PQI), a QoS flow identifier (QFI), required reliabilityinformation, and required latency information. The BS 790 may configureinformation received from UE #1 700, that is, sidelink radio resourcesand configuration information required for sidelink unicast-based datatransmission/reception, based on a sidelink unicast-based V2X datatransmission notification. The BS 790 may configure the RLC functionconfiguration parameter with reference to at least one of a cast typeprovided by the UE, the destination identifier, the PQI, the QFI, therequired reliability information, the required latency information, andthe required data rate. Examples of the RLC function configurationparameter may include at least one of the parameters in Table 3, asshown above and Table 6, as shown below.

The BS 790 may transmit an RRCReconfiguration message or anRRCConnectionReconfiguration message including the informationconfigured in step 703 to UE #1 700 in step 704. The message in step 704may include RLC function configuration parameter information requiredfor sidelink unicast-based data transmission/reception. In step 705, UE#1 700 may determine RLC function configuration parameter informationfor sidelink unicast-based data transmission/reception with UE #2 770based on the RLC function configuration parameter information receivedin step 704. The RLC function configuration parameter information mayinclude Table 3, Table 4, Table 5 and Table 6, as shown below. UE #1 700and UE #2 770 may perform the parameter configuration for sidelinkunicast data transmission including the RLC function configurationparameter for sidelink unicast-based data transmission/reception in step706.

The information through which the UE informs the BS of data rateinformation required for a V2X application, that is, V2X data, to betransmitted/received in sidelink may include at least one piece ofinformation shown in Table 4, as follows.

TABLE 4 SL-RLC-TxConfigIndex ::= SEQUENCE { dataRateIndex INTEGER(1..X), // or dataRate INTEGER (1..Y) rlcSNSize ENUMERATED {6, 12, 15,18}, pollByte PollByte, pollPDU PollPDU, ... } PollPDU ::= ENUMERATED {p4, p8, p16, p32, p64, p128, p256, p512, p1024, p2048, p4096, p6144,p8192, p12288, p16384, p20480, p24576, p28672, p32768, p40960, p49152,p57344, p65536, infinity, spare8, spare7, spare6, spare5, spare4,spare3, spare2, spare1} PollByte ::= ENUMERATED { kB1, kB2, kB5, kB8,kB10, kB15, kB25, kB50, kB75, kB100, kB125, kB250, kB375, kB500, kB750,kB1000, kB1250, kB1500, kB2000, kB3000, kB4000, kB4500, kB5000, kB5500,kB6000, kB6500, kB7000, kB7500, mB8, mB9, mB10, mB11, mB12, mB13, mB14,mB15, mB16, mB17, mB18, mB20, mB25, mB30, mB40, infinity, spare20,spare19, spare18, spare17, spare16, spare15, spare14, spare13, spare12,spare11, spare10, spare9, spare8, spare7, spare6, spare5, spare4,spare3, spare2, spare1} When PollPDU is configured as infinity orPollByte is configured as infinity, poll is transmitted if there is nomore packet in RLC after corresponding packet transmission.

In Table 4, data rate information may be indicated by a data rate indexor a data rate value.

The data rate value may be the value of a data rate required for eachV2X application.

The data rate index may be the index of a data rate required for eachV2X application. All available data rates are divided into data rates inpredetermined sections in consideration of V2X applications, and anindex is designated to each section. The data rate index may beconfigured as in Table 5, as follows.

TABLE 5 Data rate index Data rate demand 1 Lower than 1 kB 2 1 kB to 100kB 3 10 kB to 1000 kB 4 1000 kB to 5000 kB . . . . . .

The data rate information may be referenced to determine the SN size inTable 3 and/or an ARQ parameter (for example, PollPDU or PollByte) amongthe RLC function configuration parameters.

The RLC function configuration parameter may include at least one pieceof information in Table 6, as shown below.

RX-AM-RLC may correspond to an RLC function configuration parameter tobe used by a reception UE in an RLC AM mode, TX-AM-RLC may correspond toa transmit RLC function configuration parameter to be used by atransmission UE in the RLC AM (acknowledged mode), RX-UM-RLC maycorrespond to a receive RLC function configuration parameter to be usedby the reception UE in an RLC UM (unacknowledged mode), and TX-UM-RLCmay correspond to an RLC function configuration parameter to be used bythe transmission UE in the RLC UM mode.

TABLE 6 RX-AM-RLC ::= SEQUENCE { sn-FieldLength SN-FieldLengthAMOPTIONAL, t-PollRetransmit T-PollRetransmit, pollPDUPollPDU,pollBytePollByte, maxRetxThreshold ENUMERATED { t1, t2, t3, t4, t6, t8,t16, t32 } } TX-AM-RLC ::= SEQUENCE { sn-FieldLength SN-FieldLengthAMOPTIONAL, t-Reassembly T-Reassembly, t-StatusProhibit T-StatusProhibit }RX-UM-RLC ::= SEQUENCE { sn-FieldLength SN-FieldLengthUM OPTIONAL }TX-UM-RLC ::= SEQUENCE { sn-FieldLength SN-FieldLengthUM OPTIONAL,t-Reassembly T-Reassembly }

Alternatively, the configured RLC function configuration parameter maybe changed, which may be determined by the BS or the UE (UE #1 or UE#2). The RLC function configuration parameter required to be changed maybe transferred to the counterpart UE (UE #1 or UE #2).

The BS may manage mapping information between data rate information andinformation required for configuring the RLC function configurationparameter, such as the SN size in the RLC AM mode, the SN size in theRLC UM mode, and ARQ parameter configuration (for example, PollByte orPollPDU) based on data rate information required by the UE. The mappinginformation may be provided by a V2X server to the BS.

FIG. 7 illustrates when the UE is in an RRC_Connected state, and anembodiment in which the UE is in an RRC_Idle state or an RRC_Inactivestate and/or the UE is out of a coverage area may include at least oneof the following cases.

(1) RLC function configuration parameter information may be included ina V2X SIB message transmitted by the BS. The RLC function configurationparameter information included in the V2X SIB message may include atleast one of the parameters in Table 7 and Table 8, as shown below. AdataRateIndex included in Table 7 and Table 8 may refer to Table 5.

TABLE 7 SL-RLC-TxConfigListSib SEQUENCE (SIZE(1..maxSL-RLC-TxPreConfig)) OF SL-RLC-TXConfigurationSibSL-RLC-TxConfigurationSib ::= SEQUENCE { dataRateIndex INTEGER (1..X),// or dataRate INTEGER (1..Y) thresDataRate INTEGER (1..Z), rlcSNSizeENUMERATED {6, 12, 15, 18}, pollByte PollByte, pollPDU PollPDU, ... }

TABLE 8 SL-RLC-TxConfigListSib SEQUENCE (SIZE(1..maxSL-RLC-TxPreConfig)) OF SL-RLC-TXConfigurationSibSL-RLC-TxConfigurationSib ::= SEQUENCE { dataRateIndex INTEGER (1..X),// or dataRate INTEGER (1..Y) thresDataRate INTEGER (1..Z), rx-AM-RLC RX-AM-RLC, // [Table 6] tx-AM-RLC  TX-AM-RLC, // [Table 6] rx-UM-RLC RX-UM-RLC, // [Table 6] tx-UM-RLC  TX-UM-RLC // [Table 6] ... }

(2) RLC function configuration parameter information may bepreconfigured and may include at least one of the parameters in Table 9and Table 10, as shown below. A dataRateIndex included in Table 9 andTable 10 may refer to Table 5.

TABLE 9 SL-RLC-TxPreConfigList SEQUENCE (SIZE(1..maxSL-RLC-TxPreConfig)) OF SL-RLC-TXPreConfigurationSL-RLC-TxPreConfiguration ::= SEQUENCE { dataRateIndex INTEGER (1..X),// or dataRate INTEGER (1..Y) thresDataRate INTEGER (1..Z), rlcSNSizeENUMERATED {6, 12, 15, 18}, pollByte PollByte, pollPDU PollPDU, ... }

TABLE 10 SL-RLC-TxPreConfigList SEQUENCE (SIZE(1..maxSL-RLC-TxPreConfig)) OF SL-RLC-TXPreConfigurationSL-RLC-TxPreConfiguration ::= SEQUENCE { dataRateIndex INTEGER (1..X),// or dataRate INTEGER (1..Y) thresDataRate INTEGER (1..Z), rx-AM-RLC RX-AM-RLC, // [Table 6] tx-AM-RLC  TX-AM-RLC, // [Table 6] rx-UM-RLC RX-UM-RLC, // [Table 6] tx-UM-RLC  TX-UM-RLC // [Table 6] ... }

The RRC_Inactive UE or the RRC_Idle UE may receive a V2X SIB messageincluding Table 7 and Table 8 from the BS and acquire RLC functionconfiguration parameter information. The RRC_Inactive UE or the RRC_IdleUE may acquire preconfigured RLC function configuration parameterinformation of Table 9 and Table 10. The out-of-coverage UE may acquirepreconfigured RLC function configuration parameter information of Table9 and Table 10.

When the dataRateIndex is included in Table 7, Table 8, Table 9 andTable 10, an RLC function configuration parameter of the dataRateIndexcorresponding to a required data rate may be applied.

When the dataRate is included in Table 7, Table 8, Table 9 and Table 10,an RLC function configuration parameter of the dataRate corresponding toa required data rate may be applied.

When the thresDataRate is included in Table 7, Table 8, Table 9 andTable 10, the RLC function configuration parameter may be applied onlywhen a required data rate is less than thresDataRate. Alternatively,when thresDataRate is included in Table 7, Table 8, Table 9 and Table10, the RLC function configuration parameter may be applied only when arequired data rate is greater than the thresDataRate.

The RLC function configuration parameter may be configured as a set ofparameters as shown in Table 11 below, and parameters included in eachset may include at least one of the parameters in Table 6, Table 7,Table 8, Table 9 and Table 10.

TABLE 11 RLC function configuration parameter set 1 RLC functionconfiguration parameter set 2 . . . RLC function configuration parameterset N

When the BS performs a configuration in the UE, an index of an RLCfunction configuration parameter set may be indicated. When the UEinforms the counterpart UE of the RLC function configuration parameterthat is preconfigured or is selected by itself, an index of an RLCfunction configuration parameter set may be indicated. The RLC functionconfiguration parameter set of Table 11 may be indicated and/orconfigured to be linked with data rate information. For example, an RLCfunction configuration parameter set corresponding to data rate A may beindicated and/or configured. An RLC function configuration parameter setcorresponding to data rate index B may be indicated and/or configured.For example, an RLC function configuration parameter set correspondingto data rate C may be indicated and/or configured.

When RLC function configuration parameter information is configuredaccording to a UE implementation, the UE may manage the information inTable 4 to Table 11 and configure an RLC function configurationparameter, such as the SN size and/or an ARQ parameter, based on datarate information required by V2X data.

When an RLC function configuration parameter for transmitting andreceiving sidelink broadcast-based V2X data is configured and/or an RLCfunction configuration for transmitting and receiving sidelinkgroupcast-based V2X data is configured, the configuration method throughRRC signaling of the BS, the preconfigured method, the configurationmethod through PC5 signaling of the UE, and the configuration method bythe UE implementation may be applied as illustrated in FIG. 7. Table 4to Table 11 may also be applied.

FIG. 8A illustrates a method of the UE for measuring and reportingcongestion of sidelink resources according to an embodiment. In order todetermine the state of use of sidelink resources (for example, asidelink resource congestion state), the BS may make a request formeasuring and reporting congestion of a sidelink resource pool to theUE. The UE may be in the RRC_Connected state. The BS may instruct the UEto configure the measurement and report on the congestion through anRRCReconfiguration message or an RRCConnectionReconfiguration message.The configuration of the measurement and report on the congestion mayinclude at least one of an event-based report and a periodic report, aswell as at least one piece of sidelink resource pool information to bemeasured and reported.

When the BS supports configuration and allocation of LTE sidelinkresources and/or configuration and allocation of NR sidelink resources,the BS may instruct the UE to measure and report congestion of the LTEsidelink resource pool and/or the NR sidelink resource pool. The BS mayinstruct the UE to measure and report the congestion of a sidelinkresource pool of a secondary RAT. When the UE is instructed to measureand report the congestion of the sidelink resource pool of the secondaryRAT, the UE may measure this congestion through a congestion measurementscheme of the secondary RAT and report the congestion according to aconfigured report scheme. Since an LTE-based channel busy ratio (CBR)measurement and report scheme and an NR-based CBR measurement and reportscheme may be defined differently, the UE needs to know indicationinformation indicating whether to follow the LTE scheme or the NRscheme.

Referring to FIG. 8A, the UE may receive configuration of SL measurementand a report on congestion of a sidelink resource pool from the BS instep 801. The UE may determine whether the configuration includes theconfiguration of measurement and report on congestion of the LTEsidelink resource pool in step 802. When the configuration includes theconfiguration of measurement and report on congestion of the LTEsidelink resource pool based on the determination in step 802, the UEmay measure congestion of the LTE sidelink resource pool and report thecongestion according to the report configuration in step 803. Aprocedure of measuring and reporting congestion of the LTE sidelinkresource pool may correspond to a CBR measurement and report proceduredefined in LTE-V2X.

The UE may determine whether the configuration in step 801 includesconfiguration of measurement and report on congestion for the NRsidelink resource pool in step 804. When the configuration is found toinclude the configuration of measurement and report on congestion forthe NR sidelink resource pool based on the determination in step 804,the UE may measure the congestion for the NR sidelink resource pool andreport the congestion according to the report configuration in step 805.A procedure of measuring and reporting congestion of the NR sidelinkresource pool may correspond to a CBR measurement and report proceduredefined in NR-V2X.

The CBR measurement and report procedure defined in NR-V2X may includean operation procedure for determining an NR sidelink frame structure, aresource structure, a reference signal (RS), and congestion of aresource pool, and may be different from the procedure defined inLTE-V2X. When the configuration does not include the configuration ofmeasurement and report on congestion for the LTE sidelink resource poolbased on the determination in step 802, the UE may proceed to step 804.When the configuration is found not to include the configuration ofmeasurement and report on congestion for the NR sidelink resource poolbased on the determination in step 804, the UE may end the procedure.

FIG. 8B illustrates a method of the UE for measuring and reportingcongestion of sidelink resources according to an embodiment.

Referring to FIG. 8B, the UE may receive configuration of SL measurementand report on congestion for a sidelink resource pool from the BS instep 821. The UE may determine whether the configuration includes theconfiguration of measurement and report on congestion of the LTEsidelink resource pool in step 822. When the configuration includes theconfiguration of measurement and report on congestion of the LTEsidelink resource pool based on the determination in step 822, the UEmay measure congestion of the LTE sidelink resource pool and report thecongestion according to the report configuration in step 823. Theprocedure of measuring and reporting congestion of the LTE sidelinkresource pool may correspond to a CBR measurement and report proceduredefined in LTE-V2X.

The UE may determine whether the configuration in step 822 includes theconfiguration of measurement and report on congestion for the NRsidelink resource pool in step 821. When the configuration includes theconfiguration of measurement and the report on congestion for the NRsidelink resource pool based on the determination in step 822, the UEmay measure the congestion for the NR sidelink resource pool and reportthe congestion according to the report configuration in step 824. Theprocedure of measuring and reporting congestion of the NR sidelinkresource pool may correspond to a CBR measurement and report proceduredefined in NR-V2X, which may include an operation procedure fordetermining an NR sidelink frame structure, a resource structure, areference signal (RS), and congestion of a resource pool, and may bedifferent from the procedure defined in LTE-V2X.

The information indicating the configuration of measurement and reporton congestion for the LTE resource pool and the NR resource pool thatthe BS transmits to the UE in step 801 and step 821 may include at leastone of the parameters in Table 12, Table 13 and Table 14, as shownbelow.

(1) A sidelink resource pool for which congestion is measured and forwhich a report may be configured for each of LTE and NR (see Table 12)

(2) A RAT identifier indicating whether a sidelink resource pool forwhich congestion is measured and for which a report is configured forLTE or NR may be included (see Table 13)

(3) A congestion measurement and report configuration IE may beconfigured for each of LTE and NR (see Table 14)

The UE may determine LTE configuration or NR configuration according to(1), (2), or (3), and may perform a CBR measurement and report based onLTE for the corresponding sidelink resource pool or perform a CBRmeasurement and report based on NR for the corresponding sidelinkresource pool. Table 12 appears as follows.

TABLE 12 //Configuration for LTE sidelink resource pooltx-ResourcePoolToRemoveList-r14 Tx-ResourcePoolMeasList OPTIONAL, --Need ON tx-ResourcePoolToAddList-r14 Tx-ResourcePoolMeasList OPTIONAL, -- Need ON //Configuration for NR sidelink resource pooltx-ResourcePoolToRemoveList-r15 Tx-ResourcePoolMeasList OPTIONAL, --Need ON tx-ResourcePoolToAddList-r15 Tx-ResourcePoolMeasList OPTIONAL, -- Need ON Tx-ResourcePoolMeasList::= SEQUENCE (SIZE (1..maxSL- PoolToMeasure)) OFSL-V2X-TxPoolReportIdentity

As shown in Table 12, configuration for the LTE sidelink resource pooland the NR sidelink resource pool to which the CBR measurement andreport are applied may be included. Table 13 appears as follows.

TABLE 13 MeasObject ::= SEQUENCE { rat-Type ENUMERATED {LTE, NR},tx-ResourcePoolToRemoveList Tx-ResourcePoolMeasList  OPTIONAL, -- NeedON tx-ResourcePoolToAddList Tx-ResourcePoolMeasList  OPTIONAL, -- NeedON ... } Tx-ResourcePoolMeasList ::= SEQUENCE (SIZE (1..maxSL-PoolToMeasure)) OF SL-V2X-TxPoolReportIdentity

As shown in Table 13, RAT-type information to distinguish the LTEsidelink resource pool and the NR sidelink resource pool to which theCBR measurement and report are applied may be included. Table 14 appearsas follows.

TABLE 14 MeasObjectEUTRA ::= SEQUENCE { tx-ResourcePoolToRemoveList-r14 Tx-ResourcePoolMeasList  OPTIONAL, --Need ON  tx-ResourcePoolToAddList-r14 Tx-ResourcePoolMeasList OPTIONAL, -- Need ON ... } MeasObjectNR ::= SEQUENCE { tx-ResourcePoolToRemoveList-r15 Tx-ResourcePoolMeasList  OPTIONAL, --Need ON  tx-ResourcePoolToAddList-r15 Tx-ResourcePoolMeasList OPTIONAL, -- Need ON ... } Tx-ResourcePoolMeasList::= SEQUENCE (SIZE (1..maxSL- PoolToMeasure)) OFSL-V2X-TxPoolReportIdentity

As shown in Table 14, the CBR measurement report configurationinformation may include a separate CBR measurement and reportconfiguration IE for each of LTE and NR.

FIG. 9 illustrates a signal procedure for configuring a sidelinkresource allocation mode according to an embodiment.

A SidelinkUEInformation message and/or a UEAssistanceInformationmessage, transmitted when the UE informs the BS of sidelink information,may include at least one of sidelink resource allocation modes in whichthe UE is interested (BS scheduling mode 1 and UE scheduling mode 2) andsidelink RAT information in which the UE is interested (LTE RAT, NR RAT,LTE & NR RATs).

Table 15, as shown below, illustrates a SidelinkUEInformation messageincluding sidelink resource allocation mode information and sidelink RATinformation in which the UE is interested. The sidelink resourceallocation mode information and/or the sidelink RAT information in whichthe UE is interested may also be included in a UEAssistanceInformationmessage.

TABLE 15 SidelinkUEInformation-IEs ::= SEQUENCE { v2x-CommRxInterestedFreqList SL-V2X-CommFreqList  OPTIONAL, p2x-CommTxType ENUMERATED {true} OPTIONAL,  v2x-CommTxResourceReqSL-V2X-CommTxFreqList  OPTIONAL,  ... } SL-V2X-CommTxResourceReq ::=SEQUENCE {  carrierFreqCommTx INTEGER (0.. maxFreqV2X-1) OPTIONAL, v2x-TypeTxSync SL-TypeTxSync OPTIONAL,  v2x-DestinationInfoListSL-DestinationInfoList OPTIONAL,  v2x-CommInterestedMode ENUMERATED{mode1, mode2, both} OPTIONAL,  v2x-CommInterestedRAT ENUMERATED {NR,LTE, both} OPTIONAL, } SL-V2X-CommFreqList ::= SEQUENCE (SIZE(1..maxFreqV2X)) OF INTEGER (0..maxFreqV2X-1) SL-V2X-CommTxFreqList ::=SEQUENCE (SIZE (1..maxFreqV2X)) OF SL-V2X-CommTxResourceReqSL-DestinationInfoList ::= SEQUENCE (SIZE (1..maxSL-Dest)) OFSL-DestinationIdentity SL-DestinationIdentity ::= BIT STRING (SIZE (24))

The BS receiving the sidelink resource allocation mode informationand/or the sidelink RAT information in which the UE is interested mayindicate sidelink resource allocation and configuration to the UEthrough an RRCReconfiguration message or an RRCConnectionReconfigurationmessage with reference to information of interest to the UE.

Table 16 shows configuration information of the BS including at leastone of sidelink resource allocation mode information indicated to the UE(mode 1, mode 2, or mode 1 & mode 2), a destination ID list (unicast,groupcast, and broadcast destination IDs), a cast type indicator thatmay be included when it is difficult to identify a cast type throughonly a destination ID, an SLRB ID list (unicast, groupcast, andbroadcast SLRB IDs), and an RAT type (LTE RAT, NR RAT, and LTE & NRRAT). Table 16 appears as follows.

TABLE 16 SL-V2X-ConfigDedicated ::= SEQUENCE { commTxResources CHOICE { releaseNULL,  setup SEQUENCE {  scheduled SEQUENCE {  sl-V-RNTI C-RNTI, v2x-SchedulingPool SL-CommResourcePoolV2X OPTIONAL, -- Need ON mac-MainConfig  MAC-MainConfigSL,  mcs INTEGER (0..31) OPTIONAL, --Need OR  logicalChGroupInfoListLogicalChGroupInfoList, rat-TypeENUMERATED {LTE, NR, Both}, ... } OPTIONAL, ue-Selected SEQUENCE { --Pool for normal usage  v2x-CommTxPoolNormalDedicated SEQUENCE { poolToReleaseList SL-TxPoolToReleaseListV2X OPTIONAL, -- Need ON poolToAddModList SL-TxPoolToAddModListV2X OPTIONAL, -- Need ONv2x-CommTxPoolSensingConfig SL-CommTxPoolSensingConfig OPTIONAL, --NeedON  } rat-Type ENUMERATED {LTE, NR, Both}, ...  } OPTIONAL,  } }

Referring to FIG. 9, the UE #1 900 may determine whether a packet isgenerated in a V2X application, and may determine at least one of a casttype, a RAT type, and a sidelink resource allocation mode correspondingto the packet of the V2X application in step 901. The cast type maycorrespond to unicast, groupcast, or broadcast. The RAT type maycorrespond to at least one of LTE and NR. The sidelink resourceallocation mode may correspond to at least one of mode 1 and mode 2.

The UE #1 900 may inform the BS 990 of at least one of the cast type,the RAT type, and the sidelink resource allocation mode in which the UEis interested, as shown above in Table 15, in step 902. The message thatthe UE #1 900 transmits to the BS 990 in step 902 may include at leastone of a SidelinkUEInformation message or a UEAssistanceInformationmessage. The BS 990 may configure sidelink resource allocation andconfiguration information of the UE based on the information in whichthe UE is interested in step 903.

The BS 990 may transmit the sidelink resource allocation andconfiguration information to the UE as shown in Table 16, in step 904.The message that the BS 990 transmits to the UE #1 900 in step 904 mayinclude at least one of an RRCReconfiguration message or anRRCConnectionReconfiguration message. The UE #1 900 may perform a V2Xpacket transmission/reception procedure according to the receivedconfiguration information in step 905.

A method of operating SLRB configuration based on PQL, QFI, and QoSrequirements of the V2X application will now be described with referenceto FIG. 10. When PQIs, QFIs, and QoS requirements are the same ortolerant for V2X packets generated in one or more V2X applications, V2Xapplication packet transmission/reception may be performed in the sameSLRB. When PQIs, QFIs, and QoS requirements are different for V2Xpackets generated in one or more V2X applications, an SLRB correspondingto each PQI or QFI may be configured separately, and V2X applicationpacket transmission/reception may be performed.

FIG. 10A illustrates a signal procedure for operating a sidelink beareraccording to an embodiment. FIG. 10A illustrates the signal flow forconfiguring a new PC5 RRC unicast connection between UEs.

Referring to FIG. 10A, UE #1 1000 may determine the generation of a V2Xpacket corresponding to a V2X application and determine the cast type ofthe V2X packet in step 1001. When the cast type of the V2X packet isunicast, UE #1 1000 may identify whether a preset sidelink PC5 RRCconfiguration can be used in step 1002. When it is determined that a newsidelink PC5 RRC configuration is needed for the V2X packet in step1003, UE #1 1000 may perform a PC5 RRC connection configuration and SLRBconfiguration procedure with UE #2 1090 in step 1004. UE #1 1000 maydetermine to transmit the V2X packet to the configured SLRB in step 1005and may transmit the V2X packet to UE #2 1090 through the configuredSLRB in step 1006.

FIG. 10B illustrates a signal procedure for operating a sidelink bearer,i.e., the signal flow for transmitting and receiving a V2X packetthrough preset PC5 RRC unicast connection configuration information whena V2X packet for the same V2X application is generated between UEs,according to an embodiment.

Referring to FIG. 10B, UE #1 1000 and UE #2 1090 may have a PC5 RRCconfiguration and an SLRB configuration in step 1021. UE #1 1000 maydetermine the generation of a V2X packet corresponding to a V2Xapplication and determine the cast type of the V2X packet in step 1022.When the cast type of the V2X packet is unicast, UE #1 1000 maydetermine whether the V2X packet belongs to SLRB of preset sidelink PC5RRC in step 1023. When it is determined that the V2X packet can betransmitted through the preset SLRB in step 1024, UE #1 1000 maytransmit the V2X packet to UE #2 1090 through the configured SLRB instep 1025.

FIG. 10C illustrates a signal procedure for operating a sidelink bearer,i.e., illustrates the signal flow for configuring a new PC5unicast-based SLRB when a V2X packet for a new V2X application isgenerated between UEs, according to an embodiment.

Referring to FIG. 10C, UE #1 1000 and UE #2 1090 may have a PC5 RRCconfiguration and an SLRB configuration in step 1041. UE #1 1000 maydetermine the generation of a V2X packet corresponding to a V2Xapplication and determine the cast type of the V2X packet in step 1042.When the cast type of the V2X packet is unicast, UE #1 1000 maydetermine whether the V2X packet belongs to SLRB of preset sidelink PC5RRC in step 1043. When it is determined that the V2X packet cannot betransmitted through the preset SLRB in step 1044, UE #1 1000 maydetermine the necessity for a new SLRB configuration for transmittingthe V2X packet. UE #1 1000 and UE #2 1090 may perform a sidelink PC5 RRCconfiguration procedure for the new SLRB configuration in step 1045. UE#1 1000 may transmit the V2X packet to UE #2 1090 through theconfiguration SLRB in step 1046.

Although FIGS. 10A, 10B, and 10C illustrate only the signal flow betweentwo UEs for performing the PC5 RRC connection configuration procedureand the SLRB configuration procedure using the PC5 RRC connection, thesignal flow with the BS may be defined when the PC5 RRC connectionconfiguration and SLRB configuration information is received from theBS.

FIG. 11A illustrates a method of the UE for processing a sourceidentifier update for sidelink according to an embodiment. For example,on the side of peer UEs for performing sidelink unicast, a destinationidentification (DST ID) and a source identification (SRC ID) may be thesame.

SRC ID of UE #1=DST ID of UE #2

SRC ID of UE #2=DST ID of UE #2

A sidelink-based V2X system should be able to change the SRC ID in orderto prevent a problem of tracking a source UE. In the case of sidelinkunicast, since the SRC ID of the UE may correspond to the DST ID of thepeer UE, there may be a problem of changing the DST ID. Since the changein the SRC ID and the change in the DST ID may be interpreted as anindication of a new PC5 RRC connection, two UEs connected throughunicast should be able to distinguish when a change in the SRC ID andthe DST ID is needed from when a new PC5 RRC connection or a new PC5SLRB configuration is needed. When the SRC ID and the DST ID arechanged, the conventional PC5 RRC connection may be maintained. When theSRC ID and the DST ID are changed, the conventional PC5 SLRBconfiguration may be maintained.

The UE having the change in the SRC ID may provide notification of thechange in the SRC ID from an upper layer of the UE to an RRC layer, andmay inform the counterpart UE that the change in the DST ID is needed.The UE requiring the new PC5 RRC connection may provide notification ofthe necessity for the new PC5 RRC connection from an upper layer of theUE to an RRC layer. The UE may inform the counterpart UE that the newPC5 RRC connection is needed. Alternatively, the UE having the new PC5SLRB configuration may provide notification of the necessity for the newPC5 SLRB configuration from an upper layer of the UE to an RRC layer.The UE may inform the counterpart UE that the new PC5 configuration isneeded. UEs having the sidelink unicast connection may manage SLRB ID,SRC ID, and DST ID mapping information. UEs having the sidelink unicastconnection may manage an SLRB ID list mapped to PC5 RRC. UEs having thesidelink unicast connection may manage SRC ID and DST ID informationmapped to PC5 RRC.

Referring to FIG. 11A, the UE may determine whether a new PC5 RRCconnection configuration is indicated in step 1102 while a PC5 RRCconnection is maintained in step 1101. When the new PC5 RRC connectionconfiguration is indicated according to the determination in step 1102,the UE may perform a new PC5 RRC connection configuration procedure instep 1104. When a change in an SRC ID (source ID) is indicated accordingto the determination in step 1103, the UE may perform an SRC ID changeprocedure that is being used for the conventional PC5 RRC connection instep 1105. Step 1102 and step 1103 may pertain to information indicatedfrom an upper layer of one UE to an RRC layer and may be indicatedthrough a PC5 RRC connection between two UEs.

FIG. 11B illustrates a method of the UE for processing a sourceidentifier update for sidelink according to an embodiment.

Referring to FIG. 11B, the UE may determine whether a new PC5 SLRBconfiguration is indicated in step 1122 while a PC5 RRC connection ismaintained in step 1121. When the new SLRB configuration is indicatedaccording to the determination in step 1122, the UE may perform a newSLRB configuration procedure in step 1124. When a change in an SRC ID isindicated according to the determination in step 1123, the UE mayperform an SRC ID change procedure for the conventional SLRB in step1125. When a change in an SRC ID is not indicated according to thedetermination in step 1123, step 1121 is repeated. Step 1122 and step1123 may correspond to an internal procedure of one UE, which is a newSLRB configuration indication and an SRC ID change indication from anupper layer to an RRC layer, and may be a new SLRB configurationindication and an SRC ID change indication as a configuration throughthe PC5 RRC connection between two UEs connected through PC5 RRCunicast.

FIGS. 11A and 11B may be performed by two UEs connected through sidelinkunicast.

FIG. 12 illustrates a signal procedure for processing a sourceidentifier update for sidelink according to an embodiment.

Referring to FIG. 12, UE #1 1200 and UE #2 1270 may have a PC5 RRCunicast connection in step 1201. SLRB configured through the PC5 RRCunicast connection may correspond to SLRB=1. SRC ID=10 and DST ID=20 onthe side of UE #1 1200, and SRC ID=20 and DST ID=10 on the side of UE #21270. UE #1 1200 may determine the necessity for a new PC5 RRC unicastconnection or the necessity for a new SLRB configuration in step 1202.UE #1 1200 and UE #2 1270 may perform the PC5 RRC unicast connectionconfiguration and the new SLRB configuration in step 1203 and step 1204.UE #1 1200 and UE #2 1270 may have SLRB 2 in step 1205 through theprocedures in step 1203 and 1204.

In step 1206, UE #2 1270 may determine the necessity for a change in itsown SRC ID for SLRB 1, which is the DST ID of UE #1 1200. UE #2 1270 andUE #1 1200 may perform a procedure for changing a DST ID of UE 1 (thatis, an SRC ID of UE #2) for SLRB 1 in step 1207 and step 1208. Afterstep 1207 and step 1208, UE #1 1200 and UE #2 1270 may configure SRCID=10 and DST ID=30 on the side of UE #1 and configure SRC ID=30 and DSTID=10 on the side of UE #2 in accordance with SLRB 1 in step 1209.

A method of operating a sidelink logical channel priority (LCP) mayinclude at least one of the following methods.

Method 1: Priority information of a sidelink logical channelcorresponding to a V2X packet or V2X flow may use a default prioritylevel value of 5 QIs of the V2X packet or V2X flow. Examples of 5 QIsare shown in Table 17 below. A PQI which can be applied to V2X sidelinkmay be derived based on the 5 QIs, and the priority of the PQI may beconfigured to follow the default priority level value. Alternatively,the priority of the PQI may be configured based on the default prioritylevel value.

An AS layer of the UE may determine the priority value of a logicalchannel corresponding to the V2X flow or V2X packet according to thepriority level of the PQI of the V2X flow or V2X packet and execute theLCP according to the priority. For example, it is assumed that thepriority is lower as the priority value is higher. A logical channelcorresponding to V2X flow or a V2X packet having a high priority (havinga low priority value) may be preferentially scheduled. PC5 RRC may havea higher priority than the V2X packet. Table 17 appears as follows.

TABLE 17 Default Default Packet Packet Maximum Default 5QI ResourcePriority Delay Error Data Burst Averaging value Type Level Budget RateVolume Window Example Services 82 Delay 19 10 ms 10⁻⁴  255 bytes 2000 msDiscrete Critical Automation (see GBR TS 22.261 [22]) 83 22 10 ms 10⁻⁴1354 bytes 2000 ms Discrete (NOTE 3) Automation (see TS 22.261 [22]),eV2X Messages (Platooning, Cooperative Lane Change with low LoA; see TS22.186 [4]) 84 24 30 ms 10⁻⁵ 1354 bytes 2000 ms Intelligent transportsystems (see TS 22.261 [22]) 85 21  5 ms 10⁻⁵  255 bytes 2000 msElectricity Distribution- high voltage (see TS 22.261 [22]), RemoteDriving (see TS 22.186 [4]) 100 18  5 ms 10⁻⁴ 1354 bytes 2000 ms eV2Xmessages (Collision Avoidance, Platooning with high LoA (see TS 22.186[4])

Method 2: V2X layer may configure a priority value which can be appliedto a V2X packet or V2X flow. The operation of the priority valueassigned to the V2X packet or V2X flow may follow the rule of an upperlayer. An AS layer of the UE may determine the priority of a logicalchannel corresponding to the V2X flow or V2X packet based on a priorityvalue of the V2X flow or V2X packet, and may execute the LCP accordingto the priority.

For example, it is assumed that the priority is lower as the priorityvalue is higher. A logical channel corresponding to V2X flow or a V2Xpacket having a high priority (having a low priority value) may bepreferentially scheduled. PC5 RRC may have a higher priority than theV2X packet.

A method of selecting sidelink resource pools to be used for the directlink setup between UEs of a higher layer and/or PC5 RRC connection setupbetween UEs may include at least one of the following methods.

(1) Use broadcast pool until PC5 RRC connection establishment completed,and then use unicast pool for V2X data traffic.

(2) Use unicast pool for the whole direct link setup proceduresincluding PC5 RRC connection establishment.

(3) Use broadcast pool before PC5 RRC connection establishmentsignaling.

(4) Use broadcast pool before PC5 RRC connection establishment signalingwhich requires HARQ feedback.

Methods disclosed according to embodiments described herein may beimplemented by hardware, software, or a combination of hardware andsoftware.

When the methods are implemented by software, a computer-readablestorage medium for storing one or more programs (software modules) maybe provided. The one or more programs stored in the computer-readablestorage medium may be configured for execution by one or more processorswithin the electronic device. The at least one program may includeinstructions that cause the electronic device to perform the methodsaccording to embodiments of the disclosure.

The programs (software modules or software) may be stored innon-volatile memories including a random access memory and a flashmemory, a read only memory (ROM), an electrically erasable programmableread only memory (EEPROM), a magnetic disc storage device, a compactdisc-ROM (CD-ROM), digital versatile discs (DVDs), or other type opticalstorage devices, or a magnetic cassette. Alternatively, any combinationof some or all of these memories may form a memory in which the programis stored. A plurality of such memories may be included in theelectronic device.

In addition, the programs may be stored in an attachable storage devicewhich may access the electronic device through communication networkssuch as the Internet, Intranet, local area network (LAN), wide LAN(WLAN), and storage area network (SAN) or a combination thereof. Such astorage device may access the electronic device via an external port. Aseparate storage device on the communication network may access aportable electronic device.

While the disclosure has been particularly shown and described withreference to certain embodiments thereof, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope of thepresent disclosure as defined by the following claims and theirequivalents.

What is claimed is:
 1. A method by a first user equipment (UE) in awireless communication system, the method comprising: receiving a firstmessage including radio link control (RLC) function configurationparameter information from a base station (BS); and performing sidelinkcommunication with a second UE, based on the received RLC functionconfiguration parameter information.
 2. The method of claim 1, furthercomprising transmitting a SidelinkUEInformation message including datarate information for sidelink transmission to the BS in case that thefirst UE is in an RRC_Connected state, wherein the first message is aradio resource control (RRC) message, and wherein the RLC functionconfiguration parameter information is configured based on the data rateinformation included in the SidelinkUEInformation message.
 3. The methodof claim 1, wherein the first message is a system information block(SIB) message in case that the first UE is in an RRC_Inactive state oran RRC_Idle state.
 4. The method of claim 1, wherein the RLC functionconfiguration parameter information is pre-configured in case that thefirst UE is in an Out-of-coverage state.
 5. The method of claim 1,wherein the performing of the sidelink communication comprises:determining whether a condition for configuring a new sidelink radiobearer (SLRB) is satisfied; transmitting a second RRC message to thesecond UE in case that the condition is satisfied; receiving a third RRCmessage from the second UE in response to the second RRC message; andperforming the sidelink communication with the second UE.
 6. A method bya base station (BS) in a wireless communication system, the methodcomprising: transmitting a first message including radio link control(RLC) function configuration parameter information to a first userequipment (UE), wherein sidelink communication between the first UE anda second UE is performed based on the transmitted RLC functionconfiguration parameter information.
 7. The method of claim 6, furthercomprising receiving a SidelinkUEInformation message including data rateinformation for sidelink transmission to the first UE in case that thefirst UE is in an RRC_Connected state, wherein the first message is aradio resource control (RRC) message, and wherein the RLC functionconfiguration parameter information is configured based on the data rateinformation included in the SidelinkUEInformation message.
 8. The methodof claim 6, wherein the first message is a system information block(SIB) message in case that the first UE is in an RRC_Inactive state oran RRC_Idle state.
 9. The method of claim 6, wherein the RLC functionconfiguration parameter information is pre-configured in case that thefirst UE is in an Out-of-coverage state.
 10. A method by a second userequipment (UE) in a wireless communication system, the methodcomprising: receiving a second radio resource control (RRC) message froma first UE; transmitting a third RRC message to the first UE in responseto the second RRC message; and performing sidelink communication withthe first UE, wherein the second RRC message is received in case that acondition for configuring a new sidelink radio bearer (SLRB) issatisfied.
 11. A first user equipment (UE) comprising: a transceiverconfigured to transmit and receive at least one signal; and a controllerconnected to the transceiver, wherein the controller is configured toreceive a first message including radio link control (RLC) functionconfiguration parameter information from a base station (BS) and performsidelink communication with a second UE, based on the received RLCfunction configuration parameter information.
 12. The first UE of claim11, wherein the controller is further configured to transmit aSidelinkUEInformation message including data rate information forsidelink transmission to the BS in case that the first UE is in anRRC_Connected state, wherein the first message is a radio resourcecontrol (RRC) message, and wherein the RLC function configurationparameter information is configured based on the data rate informationincluded in the SidelinkUEInformation message.
 13. The first UE of claim11, wherein the first message is a system information block (SIB)message in case that the first UE is in an RRC_Inactive state or anRRC_Idle state.
 14. The first UE of claim 11, wherein the RLC functionconfiguration parameter information is pre-configured in case that thefirst UE is in an Out-of-coverage state.
 15. The first UE of claim 11,wherein the controller is further configured to: determine whether acondition for configuring a new sidelink radio bearer (SLRB) issatisfied, transmit a second RRC message to the second UE in case thatthe condition is satisfied, receive a third RRC message from the secondUE in response to the second RRC message, and perform the sidelinkcommunication with the second UE.
 16. A base station (BS) comprising: atransceiver configured to transmit and receive at least one signal; anda controller connected to the transceiver, wherein the controller isconfigured to transmit a first message including radio link control(RLC) function configuration parameter information to a first userequipment (UE), and wherein sidelink communication between the first UEand a second UE is performed based on the transmitted RLC functionconfiguration parameter information.
 17. The BS of claim 16, wherein thecontroller is further configured to receive a SidelinkUEInformationmessage including data rate information for sidelink transmission to thefirst UE in case that the first UE is in an RRC_Connected state, whereinthe first message is a radio resource control (RRC) message, and whereinthe RLC function configuration parameter information is configured basedon the data rate information included in the SidelinkUEInformationmessage.
 18. The BS of claim 16, wherein the first message is a systeminformation block (SIB) message in case that the first UE is in anRRC_Inactive state or an RRC_Idle state.
 19. The BS of claim 16, whereinthe RLC function configuration parameter information is pre-configured,in case that the first UE is in an Out-of-coverage state.
 20. A seconduser equipment (UE) comprising: a transceiver configured to transmit andreceive at least one signal; and a controller connected to thetransceiver, wherein the controller is configured to receive a secondradio resource control (RRC) message from a first UE, transmit a thirdRRC message to the first UE in response to the second RRC message, andperform sidelink communication with the first UE, and wherein the secondRRC message is received in case that a condition for configuring a newsidelink radio bearer (SLRB) is satisfied.